Add PRESUBMIT to enforce usage of new Googletest APIs.
Add PRESUBMIT to enforce usage of new Googletest APIs.

Example of an error:
** Presubmit ERRORS **
Usage of legacy GoogleTest API detected!
Please use the new API: https://github.com/google/googletest/blob/master/googletest/docs/primer.md#beware-of-the-nomenclature.
Affected files:

  rtc_base/ssl_stream_adapter_unittest.cc (line 1459)

Bug: None
No-Try: True
Change-Id: Ibe8fbbc6c3205a266fc75afb5b59721a6b69f240
Reviewed-on: https://webrtc-review.googlesource.com/c/120924
Reviewed-by: Karl Wiberg <2c708eb0a58047bf403399f50b3da33ffd2dd444@webrtc.org>
Reviewed-by: Oleh Prypin <5baa3e04f9bd6ba7a2a4b56625a3c84f19237cdb@webrtc.org>
Commit-Queue: Mirko Bonadei <d2c43c210eae6feef04f53bae50885e8152edcca@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#26562}
TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc